Gifford said Jennifer Graves, Joshua Powell's sister, and her husband recently visited Joshua in Washington state, where he now lives, to spend time with the children. But when Graves confronted her brother about his wife's disappearance, Joshua asked her to leave his house.

Tuesday, Graves publicly questioned her brother's behavior on the "Dr. Phil Show," saying she hopes he did not commit a crime but "the truth is going to come out eventually."

"The thing that has bothered me the most about Josh's behavior is that he has been uncooperative with the police in giving them any details. He also has been very neglected to participate in the media. That's our biggest tool in helping find Susan. You're [the] husband, there's more that you can do. So get up and do it," Graves said.

At a press conference Monday to announce a foundation in Susan Powell's name, her friends and family said it wasn't until they spoke to each other that they put together what they believe are the missing pieces of Susan Powell's life.

Some alleged that Joshua would not let his wife have her own car key and she had to get permission from him to use the family vehicle.

One said he knew of an episode of physical violence and another said Joshua would frequently change the pin numbers on their bank accounts so Susan would not have access to their money.

Gifford said, "people who were in the house with firsthand knowledge" knew that Joshua Powell would purposefully undermine his wife's parenting in front of their children.

"He would go in and get the boys out of bed and say things like, 'Mommy's so mean for making you go to bed, come on out of bed,'" Gifford said.

Joshua Powell and his attorney have refused to comment directly on the latest allegations.

In an e-mail to ABC News, his attorney said he believes supporters of Joshua Powell are preparing a response to the "untrue allegations."

Joshua Powell Moved to Washington State

Friends and family said they were surprised when Joshua Powell began to pack up the family's belongings and move out of state.

Last month, police told ABC News there was nothing they could do to prevent Joshua Powell from relocating about 800 miles away in Washington state.

"Josh has been free to come and go," West Valley City Assistant Police Chief Craig Black said. "And we're still waiting for Josh to cooperate with us and talk with us."

Susan Powell was reported missing the day after Joshua Powell packed up the couple's young sons for a middle-of-the-night camping trip in below-freezing temperatures. It was a trip, her family has since said, that Susan Powell would have never allowed.